Improved synthesis of 4-ethylsulfonyl-1-naphthalenesulfonamide

4-Ethylsulfonyl-1-naphthalenesulfonamide (1,ENS), reported to promote experimental bladder carcinogenesis was prepared in a convenient, high-yield, five-step synthesis from 1-naphthalenethiol (2). After conversion of 2 to the ethylthioether (3) by a standard procedure, 3 was sulfonated using one equivalent of cholosulfonic acid to yield the sulfonic acid (4) which was isolated as the sodium salt (5). The acid chloride (6) was prepared from 5 by reaction with chlorosulfonic acid in anhydrous C HCl/sub 3/, and treatment of 6 with ammonia gave the thioether sulfonamide (7), which was converted to ENS by peroxide oxidation. Overall conversion yields were reported as 50--60 percent. (BLM)